We have previously described that the concentration of insulin receptors on IM-9 lymphocytes is inversely related to the ambient insulin level. This homeostatic regulation of insulin receptor concentration by insulin is dependent upon the duration and concentration of insulin. Insulin analogue studies have shown that the loss of receptors is mediated via the receptor in direct proportion to the bioaffinity of the analogues. The response is temperature dependent and requires protein synthesis. Studies involving protein synthesis inhibitors are now being carried out in order to elucidate the fate of the receptors under our experimental conditions.